Utilization of quantum wires in MEMS actuators

ABSTRACT

A mesh of quantum wires is utilized in a non-conductive material to improve its conductivity. The non-conductive material can be highly expansive interposed in the mesh. The expansive material is ideally polytetrafluoroethylene which has a high coefficient of thermal expansion and the wires can comprise carbon nanotubes.

FIELD OF THE INVENTION

The present invention relates to a thermal actuator device and, in particular, discloses a method of utilisation of quantum wires in MEMS actuators.

The present invention further relates to the construction of micro-electro mechanical systems (MEMS).

BACKGROUND OF THE INVENTION

MEMS processes are often characterised by the construction of conductive layers in multilayered structures such as actuator devices or the like. Often, it is important for these conductive layers to be in thermal contact with an adjacent material where the conductive layer is utilised as a heater element to instigate the actuation of an active device of the micro-electro mechanical system. The conductive layer material is typically a different material than the material utilised in the adjacent, thermally active layer, creating problems associated with the formation of such active, multilayered structures such as de-lamination and in-efficient thermal connection which can cause problems in the device performance and ultimately devices may stop functioning.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a MEMS construction which alleviates the aforementioned problems.

In accordance with a first aspect of the present invention there is provided a method of constructing one or more electrically conductive portions within a substantially non-conductive material comprising embedding quantum wires of a substantially conductive material within said portions.

In accordance with a second aspect of the present invention there is provided a thermal actuator comprising a substantially non-conductive, heat expansive material having a predetermined portion thereof rendered electrically conductive by the incorporation of a series of quantum wires of a substantially conductive material.

Preferably, the non-conductive, expansive material comprises substantially polytetrafluoroethylene and the conductive material comprises substantially copper.

In accordance with a third aspect of the present invention there is provided a thermal actuator comprising first and second layers of substantially non-conductive, heat expansive materials, wherein one of said layers incorporates quantum wires of a substantially conductive material interposed with said substantially non-conductive, expansive material.

Preferably, the non-conductive, expansive material comprises substantially polytetrafluoroethylene and the conductive material comprises substantially copper.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings which:

FIG. 1 is a cut out topside view of illustrating two adjoining inject nozzles constructed in accordance with the preferred embodiment.

FIG. 2 is an exploded perspective view illustrating the construction of a single inject nozzle in accordance with the preferred embodiment.

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

The preferred embodiment of the present invention will be described in respect of an ink jet print head construction which utilises quantum wires embedded in a thermal expansion layer. The present invention should, however, not necessarily be restricted to the field of ink jet printing, as will be readily evident.

In the preferred embodiment, an inkjet nozzle is provided having a thermally based actuator which is highly energy efficient. The thermal actuator is located within an chamber filled with ink and relies upon the thermal expansion of materials when an electric current is being passed through them to activate the actuator thereby causing the ejection of ink out of a nozzle provided in the nozzle chamber.

Turning to FIG. 1, there are illustrated two adjoining inkjet nozzles 10 constructed in accordance with the preferred embodiment. Each nozzle 10, can be constructed as part of an array of nozzles on a silicon wafer device and can be constructed utilising semiconductor processing techniques in addition to micro machining and micro fabrication process technology (MEMS) and a full familiarity with these technologies is hereinafter assumed.

The nozzle chamber 10 includes a ink ejection port 11 for the ejection of ink from within the nozzle chamber. Ink is supplied via an inlet port 12 which has a grill structure fabricated from a series of posts 14, the grill acting to filter out foreign bodies within the ink supply and also to provide stability to the nozzle chamber structure. Inside the nozzle chamber is constructed a thermal actuator device 16 which is interconnected to an electric circuit (not shown) which, when thermally actuated, acts as a paddle bending upwards so as to cause the ejection of ink from each ink ejection port 11. A series of etchant holes e.g. 18 are also provided in the top of nozzle chamber 10, the holes 18 being provided for manufacturing purposes only so to allow a sacrificial etchant to easily etch away the internal portions of nozzle chamber 10. The etchant ports 18 are of a sufficiently small diameter so that the resulting surface tension holds the ink within chamber 10 such that no ink leaks out via ports 18.

The thermal actuator 16 is composed primarily of polytetrafluoroethylene (PTFE) which is a generally hydrophobic material. The top layer of the actuator 16 is treated or coated so as to make it hydrophilic and thereby attract water/ink via inlet port 12. Suitable treatments include plasma exposure in an ammonia atmosphere. The bottom surface remains hydrophobic and repels the water from the underneath surface of the actuator 16. Underneath the actuator 16 is provided a further surface 19 also composed of a hydrophobic material such as PTFE. The surface 19 has a series of holes 20 in it which allow for the flow of air into the nozzle chamber 10. The diameter of the nozzle holes 20 again being of such a size so as to restrict the flow of fluid out of the nozzle chamber via surface tension interactions. out of the nozzle chamber.

The surface 19 is separated from a lower level 23 by means of a series of spaced apart posts e.g. 22 which can be constructed when constructing the layer 19 utilising an appropriate mask. The nozzle chamber 10, but for grill inlet port 12, is walled on its sides by silicon nitride walls e.g. 25,26. An air inlet port is formed between adjacent nozzle chambers such that air is free to flow between the walls 25,28. Hence, air is able to flow down channel 29 and along channel 30 and through holes e.g. 20 in accordance with any fluctuating pressure influences.

The air flow acts to reduce the vacuum on the back surface of actuator 16 during operation. As a result, less energy is required for the movement of the actuator 16. In operation, the actuator 16 is thermally actuated so as to move upwards and cause ink ejection. As a result, air flows in along channels 29,30 and through the holes e.g. 20 into the bottom area of actuator 16. Upon deactivation of the actuator 16, the actuator lowers with a corresponding airflow out of port 20 along channel 30 and out of channel 29. Any fluid within nozzle chamber 10 is firstly repelled by the hydrophobic nature of the bottom side of the surface of actuator 16 in addition to the top of the surface 19 which is again hydrophobic. As noted previously the limited size holes e.g. 20 further stop the fluid from passing the holes 20 as a result of surface tension characteristics.

A further preferable feature of nozzle chamber 10 is the utilisation of the nitride posts 14 to also clamp one end of the surfaces 16 and 19 firmly to bottom surface 20 thereby reducing the likelihood delaminating during operation.

In FIG. 2, there is illustrated an exploded perspective view of a single nozzle arrangement 10. The exploded perspective view illustrates the form of construction of each layer of a simple nozzle arrangement 10. The nozzle arrangement can be constructed on a base silicon wafer 34 having a top glass layer which includes the various drive and control circuitry and which, for example, can comprise a two level metal CMOS layer with the various interconnects (not shown). On top of the layer 35 is first laid out a nitride passivation layer 23 of approximately one micron thickness which includes a number of vias (not shown) for the interconnection of the subsequent layers to the CMOS layer 35. The nitride layer is provided primarily to protect lower layers from corrosion or etching, especially where sacrificial etchants are utilized. Next, a one micron PTFE layer 19 is constructed having the aforementioned holes e.g. 20 and posts 22. The structure of the PTFE layer 19 can be formed by first laying down a sacrificial glass layer (not shown) onto which the PTFE layer 19 is deposited. The PTFE layer 19 includes various features, for example, a lower ridge portion 38 in addition to a hole 39 which acts as a via for the subsequent material layers.

The actuator proper is formed from two PTFE layers 40,41. The lower PTFE layer 40 is made conductive. The PTFE layer 40 can be made conductive utilising a number of different techniques including:

(i) Doping the PTFE layer with another material so as to make it conductive.

(ii) Embedding within the PTFE layer a series of quantum wires constructed from such a material as carbon nano-tubes created in a mesh form. ("Individual single-wall carbon nano-tubes as quantum wires" by Tans et al Nature, Volume 386, 3rd April 1997 at pages 474-477). The PTFE layer 40 includes tubes certain cut out portions e.g. 43 so that a complete circuit is formed around the PTFE actuator 40. The cut out portions can be optimised so as to regulate the resistive heating of the layer 40 by means of providing constricted portions so as to thereby increase the heat generated in various "hot spots" as required. A space is provided between the PTFE layer 19 and the PTFE layer 40 through the utilisation of an intermediate sacrificial glass layer (not shown).

On top of the PTFE layer 40 is deposited a second PTFE layer 41 which can be a standard non conductive PTFE layer and can include filling in those areas in the lower PTFE layer e.g. 43 which are not conductive. The top of the PTFE layer is further treated or coated to make it hydrophilic.

Next, a nitride layer can be deposited to form the nozzle chamber proper. The nitride layer can be formed by first laying down a sacrificial glass layer and etching the glass layer to form walls e.g. 25, 26 and grilled portion e.g. 14. Preferably, the mask utilised results a first anchor portion 45 which mates with the hole 39 in layer 19 so as to fix the layer 19 to the nitride layer 23. Additionally, the bottom surface of the grill 14 meets with a corresponding step 47 in the PTFE layer 41 so as to clamp the end portion of the PTFE layers 41,40 and 39 to the wafer surface so as to guard against delamination. Next, a top nitride layer 50 can be formed having a number of holes e.g. 18 and nozzle hole 11 around which a rim can be etched through etching of the nitride layer 50. Subsequently, the various sacrificial layers can be etched away so as to release the structure of the thermal actuator.

Obviously, large arrays of inkjet nozzles 10 can be created side by side on a single wafer. The ink can be supplied via ink channels etched through the wafer utilising a high density low pressure plasma etching system such as that supplied by Surface Technology Systems of the United Kingdom.

The foregoing describes only one embodiment of the invention and many variations of the embodiment will be obvious for a person skilled in the art of semi conductor, micro mechanical fabrication. Certainly, various other materials can be utilised in the construction of the various layers.

It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiment without departing from the spirit or scope of the invention as broadly described. The present embodiment is, therefore, to be considered in all respects to be illustrative and not restrictive.

Ink Jet Technologies

The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable.

The most significant problem with thermal inkjet is power consumption. This is approximately 100 times that required for high speed, and stems from the energy-inefficient means of drop ejection. This involves the rapid boiling of water to produce a vapor bubble which expels the ink. Water has a very high heat capacity, and must be superheated in thermal inkjet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out.

The most significant problem with piezoelectric inkjet is size and cost. Piezoelectric crystals have a very small deflection at reasonable drive voltages, and therefore require a large area for each nozzle. Also, each piezoelectric actuator must be connected to its drive circuit on a separate substrate. This is not a significant problem at the current limit of around 300 nozzles per print head, but is a major impediment to the fabrication of pagewide print heads with 19,200 nozzles.

Ideally, the inkjet technologies used meet the stringent requirements of in-camera digital color printing and other high quality, high speed, low cost printing applications. To meet the requirements of digital photography, new inkjet technologies have been created. The target features include:

low power (less than 10 Watts)

high resolution capability (1,600 dpi or more)

photographic quality output

low manufacturing cost

small size (pagewidth times minimum cross section)

high speed (<2 seconds per page).

All of these features can be met or exceeded by the inkjet systems described below with differing levels of difficulty. 45 different inkjet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the table below.

The inkjet designs shown here are suitable for a wide range of digital printing systems, from battery powered one-time use digital cameras, through to desktop and network printers, and through to commercial printing systems

For ease of manufacture using standard process equipment, the print head is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the print head is 100 mm long, with a width which depends upon the inkjet type. The smallest print head designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The print heads each contain 19,200 nozzles plus data and control circuitry.

Ink is supplied to the back of the print head by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The print head is connected to the camera circuitry by tape automated bonding.

Cross-Referenced Applications

The following table is a guide to cross-referenced patent applications filed concurrently herewith and discussed hereinafter with the reference being utilized in subsequent tables when referring to a particular case:

    __________________________________________________________________________     Docket                                                                             US Patent                                                                  No. Application No.                                                                        Title                                                              __________________________________________________________________________     IJ01US                                                                             09/112,751                                                                             Radiant Plunger Ink Jet Printer                                    IJ02US                                                                             09/112,787                                                                             Electrostatic Ink Jet Printer                                      IJ03US                                                                             09/112,802                                                                             Planar Thermoelastic Bend Actuator Ink Jet                         IJ04US                                                                             09/112,803                                                                             Stacked Electrostatic Ink Jet Printer                              IJ05US                                                                             09/113,097                                                                             Reverse Spring Lever Ink Jet Printer                               IJ06US                                                                             09/113,099                                                                             Paddle Type Ink Jet Printer                                        IJ07US                                                                             09/113,084                                                                             Permanent Magnet Electromagnetic Ink Jet Printer                   IJ08US                                                                             09/113,066                                                                             Planar Swing Grill Electromagnetic Ink Jet Printer                 IJ09US                                                                             09/112,778                                                                             Pump Action Refill Ink Jet Printer                                 IJ10US                                                                             09/112,779                                                                             Pulsed Magnetic Field Ink Jet Printer                              IJ11US                                                                             09/113,077                                                                             Two Plate Reverse Firing Electromagnetic Ink Jet Printer           IJ13US                                                                             09/112,818                                                                             Gear Driven Shutter Ink Jet Printer                                IJ14US                                                                             09/112,816                                                                             Tapered Magnetic Pole Electromagnetic Ink Jet Printer              IJ15US                                                                             09/112,772                                                                             Linear Spring Electromagnetic Grill Ink Jet Printer                IJ16US                                                                             09/112,819                                                                             Lorenz Diaphragm Electromagnetic Ink Jet Printer                   IJ17US                                                                             09/112,815                                                                             PTFE Surface Shooting Shuttered Oscillating Pressure Ink Jet                   Printer                                                            IJ18US                                                                             09/113,096                                                                             Buckle Grip Oscillating Pressure Ink Jet Printer                   IJ19US                                                                             09/113,068                                                                             Shutter Based Ink Jet Printer                                      IJ20US                                                                             09/113,095                                                                             Curing Calyx Thermoelastic Ink Jet Printer                         IJ21US                                                                             09/112,808                                                                             Thermal Actuated Ink Jet Printer                                   IJ22US                                                                             09/112,809                                                                             Iris Motion Ink Jet Printer                                        IJ23U5                                                                             09/112,780                                                                             Direct Firing Thermal Bend Actuator Ink Jet Printer                IJ24U5                                                                             09/113,083                                                                             Conductive PTFE Ben Activator Vented Ink Jet Printer               IJ25US                                                                             09/113,121                                                                             Magnetostrictive Ink Jet Printer                                   IJ26U5                                                                             09/113,122                                                                             Shape Memory Alloy Ink Jet Printer                                 IJ27U5                                                                             09/112,793                                                                             Buckle Plate Ink Jet Printer                                       IJ28U5                                                                             09/112,794                                                                             Thermal Elastic Rotary Impeller Ink Jet Printer                    IJ29U5                                                                             09/113,128                                                                             Thermoelastic Bend Actuator Ink Jet Printer                        IJ30US                                                                             09/113,127                                                                             Thermoelastic Bend Actuator Using PTFE and Corrugated                          Copper Ink Jet Printer                                             IJ31US                                                                             09/112,756                                                                             Bend Actuator Direct Ink Supply Ink Jet Printer                    IJ32US                                                                             09/112,755                                                                             A High Young's Modulus Thermoelastic Ink Jet Printer               IJ33US                                                                             09/112,754                                                                             Thermally actuated slotted chamber wall ink jet printer            IJ34U5                                                                             09/112,811                                                                             Ink Jet Printer having a thermal actuator comprising an                        external coiled spring                                             IJ35U5                                                                             09/112,812                                                                             Trough Container Ink Jet Printer                                   IJ36U5                                                                             09/112,813                                                                             Dual Chamber Single Vertical Actuator Ink Jet                      IJ37US                                                                             09/112,814                                                                             Dual Nozzle Single Horizontal Fulcrum Actual or Ink Jet            IJ38US                                                                             09/112,764                                                                             Dual Nozzle Single Horizontal Actuator Ink Jet                     IJ39U5                                                                             09/112,765                                                                             A single bend actuator cupped paddle inkjet printing device        IJ40US                                                                             09/112,767                                                                             A thermally actuated inkjet printer having a series of                         thermal                                                                        actuator units                                                     IJ41US                                                                             09/112,768                                                                             A thermally actuated inkjet printer including a tapered                        heater                                                                         element                                                            IJ42US                                                                             09/112,807                                                                             Radial Back-Curing Thermoelastic Ink Jet                           IJ43US                                                                             09/112,806                                                                             Inverted Radial Back-Curing Thermoelastic Ink Jet                  IJ44U5                                                                             09/112,820                                                                             Surface bend actuator vented ink supply ink jet printer            IJ45US                                                                             09/112,821                                                                             Coil Actuated Magnetic Plate Ink Jet Printer                       __________________________________________________________________________

Tables of Drop-on-Demand Inkjets

Eleven important characteristics of the fundamental operation of individual inkjet nozzles have been identified. These characteristics are largely orthogonal, and so can be elucidated as an eleven dimensional matrix. Most of the eleven axes of this matrix include entries developed by the present assignee.

The following tables form the axes of an eleven dimensional table of inkjet types.

Actuator mechanism (18 types)

Basic operation mode (7 types)

Auxiliary mechanism (8 types)

Actuator amplification or modification method (17 types)

Actuator motion (19 types)

Nozzle refill method (4 types)

Method of restricting back-flow through inlet (10 types)

Nozzle clearing method (9 types)

Nozzle plate construction (9 types)

Drop ejection direction (5 types)

Ink type (7 types)

The complete eleven dimensional table represented by these axes contains 36.9 billion possible configurations of inkjet nozzle. While not all of the possible combinations result in a viable inkjet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain inkjet types have been investigated in detail. These are designated IJ01 to IJ45 above.

Other inkjet configurations can readily be derived from these 45 examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into inkjet print heads with characteristics superior to any currently available inkjet technology.

Where there are prior art examples known to the inventor, one or more of these examples are listed in the examples column of the tables below. The IJ01 to IJ45 series are also listed in the examples column. In some cases, a printer may be listed more than once in a table, where it shares characteristics with more than one entry.

Suitable applications include: Home printers, Office network printers, Short run digital printers, Commercial print systems, Fabric printers, Pocket printers, Internet WWW printers, Video printers, Medical imaging, Wide format printers, Notebook PC printers, Fax machines, Industrial printing systems, Photocopiers, Photographic minilabs etc.

The information associated with the aforementioned 11 dimensional matrix are set out in the following tables.

       - Description Advantages Disadvantages Examples        ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)        Actuator        Mechanism        Thermal An electrothermal heater heats the ♦Large force      generated ♦High power ♦Canon Bubblejet             bubble ink to above boiling point, ♦Simple construct       ion ♦Ink carrier limited to water 1979 Endo et al GB             transferring significant heat to the ♦No moving      parts ♦Low efficiency patent 2,007,162         aqueous ink. A bubble nucleates and ♦Fast operation      ♦High temperatures required ♦Xerox heater-in-       pit         quickly forms, expelling the ink. ♦Small chip area      required for ♦High mechanical stress 1990 Hawkins et al           The efficiency of the process is low, actuator ♦Unusua       l materials required U.S. Pat. No. 4,899,181         with typically less than 0.05% of the  ♦Large drive      transistors ♦Hewlett-Packard TIJ         electrical energy being transformed  ♦Cavitation causes        actuator failure 1982 Vaught et al         into kinetic energy of the drop.  ♦Kogation reduces      bubble formation U.S. Pat. No. 4,490,728           ♦Large print heads are difficult to           fabricate        Piezoelectric A piezoelectric crystal such as lead ♦Low      power consumption. ♦Very large area required for actuator      ♦Kyser et al U.S. Pat. No.         lanthanum zirconate (PZT) is ♦Many ink types can be      used ♦Difficult to integrate with electronics 3,946,398           electrically activated, and either ♦Fast operation      ♦High voltage drive transistors ♦Zoltan U.S.        Pat. No.         expands, shears, or bends to apply ♦High efficiency      required 3,683,212         pressure to the ink, ejecting drops.  ♦Full pagewidth      print heads impractical ♦1973 Stemme U.S. Pat. No.                  due to actuator size 3,747,120           ♦Requires electrical poling in high field .diamond-sol       id.Epson Stylus           strengths during manufacture ♦Tektronix            ♦IJ04        Electro- An electric field is used to activate ♦Low      power consumption ♦Low maximum strain (approx. 0.01%)      ♦Seiko Epson, Usui et        strictive electrostriction in relaxor materials ♦Many      ink types can be used ♦Large area required for actuator      all JP 253401/96         such as lead lanthanum zirconate ♦Low thermal expansion        due to low strain ♦IJ04         titanate (PLZT) or lead magnesium ♦Electric field      strength ♦Response speed is marginal (˜10 μs)            niobate (PMN). required (approx. 3.5 V/μm) ♦High      voltage drive transistors required          can be generated without ♦Full pagewidth print heads      impractical          difficulty due to actuator size          ♦Does not require electrical          poling        Ferroelectric An electric field is used to induce a ♦Low        power consumption ♦Difficult to integrate with electronic       s ♦IJ04         phase transition between the ♦Many ink types can be      used ♦Unusual materials such as PLZSnT are         antiferroelectric (AFE) and ♦Fast operation (<1 μs)      required         ferroelectric (FE) phase. Perovskite ♦Relatively high      longitudinal ♦Actuators require a large area         materials such as tin modified lead strain         lanthanum zirconate titanate ♦High efficiency         (PLZSnT) exhibit large strains of up ♦Electric field      strength of         to 1% associated with the AFE to FE around 3 V/μm can be         phase transition, readily provided        Electrostatic Conductive plates are separated by a ♦Low      power consumption ♦Difficult to operate electrostatic      ♦IJ02, IJ04        plates compressible or fluid dielectric ♦Many ink types      can be used devices in an aqueous environment         (usually air). Upon application of a ♦Fast operation      ♦The electrostatic actuator will normally         voltage, the plates attract each other  need to be separated from the        ink         and displace ink, causing drop  ♦Very large area      required to achieve         ejection. The conductive plates may  high forces         be in a comb or honeycomb  ♦High voltage drive transisto       rs may be         structure, or stacked to increase the  required         surface area and therefore the force.  ♦Full pagewidth      print heads are not           competitive due to actuator size        Electrostatic A strong electric field is applied to ♦Low        current consumption ♦High voltage required .diamond-solid       .1989 Saito et al, U.S. Pat. No.        pull on ink the ink, whereupon electrostatic ♦Low      temperature ♦May be damaged by sparks due to air 4,799,068         attraction accelerates the ink towards  breakdown ♦1989        Miura et al,         the print medium.  ♦Required field strength increases      as the U.S. Pat. No. 4,810,954           drop size decreases ♦Tone-jet           ♦High voltage drive transistors required           ♦Electrostatic field attracts dust        Permanent An electromagnet directly attracts a ♦Low      power consumption ♦Complex fabrication ♦IJ07,        IJ10        magnet permanent magnet, displacing ink ♦Many ink types      can be used ♦Permanent magnetic material such as        electro- and causing drop ejection. Rare earth ♦Fast      operation Neodymium Iron Boron (NdFeB)        magnetic magnets with a field strength around ♦High      efficiency required.         1 Tesla can be used. Examples are: ♦Easy extension from        single ♦High local currents required         Samarium Cobalt (SaCo) and nozzles to pagewidth print ♦C       opper metalization should be used for         magnetic materials in the heads long electromigration lifetime and      low         neodymium iron boron family  resistivity         (NdFeB, NdDyFeBNb, NdDyFeB,  ♦Pigmented inks are      usually infeasible         etc)  ♦Operating temperature limited to the           Curie temperature (around 540 K)        Soft magnetic A solenoid induced a magnetic field ♦Low      power consumption ♦Complex fabrication ♦IJ01,        IJ05, IJ08, IJ10        core electro- in a soft magnetic core or yoke ♦Many ink      types can be used ♦Materials not usually present in a      ♦IJ12, IJ14, IJ15, IJ17        magnetic fabricated from a ferrous material ♦Fast      operation CMOS fab such as NiFe, CoNiFe, or         such as electroplated iron alloys such ♦High efficiency        CoFe are required         as CoNiFe [1], CoFe, or NiFe alloys. ♦Easy extension      from single ♦High local currents required         Typically, the soft magnetic material nozzles to pagewidth print      ♦Copper metalization should be used for         is in two parts; which are normally heads long electromigration      lifetime and low         held apart by a spring. When the  resistivity         solenoid is actuated, the two parts  ♦Electroplating is        required         attract, displacing the ink.  ♦High saturation flux      density is required           (2.0-2.1 T is achievable with CoNiFe           [1])        Magnetic The Lorenz force acting on a current ♦Low power        consumption ♦Force acts as a twisting motion .diamond-sol       id.IJ06, IJ11, IJ13, IJ16        Lorenz force carrying wire in a magnetic field is ♦Many      ink types can be used ♦Typically, only a quarter of the           utilized. ♦Fast operation solenoid length provides      force in a         This allows the magnetic field to be ♦High efficiency      useful direction         supplied externally to the print head, ♦Easy extension      from single ♦High local currents required         for example with rare earth nozzles to pagewidth print ♦       Copper metalization should be used for         permanent magnets. heads long electromigration lifetime and low              Only the current carrying wire need  resistivity         be fabricated on the print-head,  ♦Pigmented inks are      usually infeasible         simplifying materials requirements.        Magneto- The actuator uses the giant ♦Many ink types can        be used ♦Force acts as a twisting motion ♦F       ischenbeck, U.S. Pat. No.        striction magnetostrictive effect of materials ♦Fast      operation ♦Unusual materials such as Terfenol-D 4,032,929         such as Terfenol-D (an alloy of ♦Easy extension from      single are required ♦IJ25         terbium, dysprosium and iron nozzles to pagewidth print .diamond-solid       .High local currents required         developed at the Naval Ordnance heads ♦Copper metalizati       on should be used for         Laboratory, hence Ter-Fe-NOL). For ♦High force is      available long electromigration lifetime and low         best efficiency, the actuator should  resistivity         be pre-stressed to approx. 8 MPa.  ♦Pre-stressing may      be required        Surface Ink under positive pressure is held in ♦Low      power consumption ♦Requires. supplementary force to effect        ♦Silverbrook, EP 0771        tension a nozzle by surface tension. The ♦Simple      construction drop separation 658 A2 and related        reduction surface tension of the ink is reduced ♦No      unusual materials ♦Requires special ink surfactants patent        applications         below the bubble threshold, causing required in fabrication .diamond-s       olid.Speed may be limited by surfactant         the ink to egress from the nozzle. ♦High efficiency      properties          ♦Easy extension from single          nozzles to pagewidth print          heads        Viscosity The ink viscosity is locally reduced ♦Simple      construction ♦Requires supplementary force to effect      ♦Silverbrook, EP 0771        reduction to select which drops are to be ♦No unusual      materials drop separation 658 A2 and related         ejected. A viscosity reduction can be required in fabrication      ♦Requires special ink viscosity patent applications               achieved electrothermally with most ♦Easy      extension from single properties         inks, but special inks can be nozzles to pagewidth print .diamond-soli       d.High speed is difficult to achieve         engineered for a 100:1 viscosity heads ♦Requires      oscillating ink pressure         reduction.  ♦A high temperature difference           (typically 80 degrees) is required        Acoustic An acoustic wave is generated and ♦Can operate      without a ♦Complex drive circuitry ♦1993      Hadimioglu et         focused upon the drop ejection nozzle plate. ♦Complex      fabrication al, EUP 550,192         region.   ♦Low efficiency ♦1993 Elrod et      al, EUP           ♦Poor control of drop position 572,220           ♦Poor control of drop volume        Thermoelastic An actuator which relies upon ♦Low power      consumption ♦Efficient aqueous operation requires a      ♦IJ03, IJ09, IJ17, IJ18        bend actuator differential thermal expansion upon ♦Many      ink types can be used thermal insulator on the hot side ♦IJ       19, IJ20, IJ21, IJ22         Joule heating is used. ♦Simple planar fabrication      ♦Corrosion prevention can be difficult ♦IJ23,        IJ24, IJ27, IJ28          ♦Small chip area required for ♦Pigmented        inks may be infeasible, as ♦IJ29, IJ30, IJ31, IJ32               each actuator pigment particles may jam the bend ♦       IJ33, IJ34, IJ35, IJ36          ♦Fast operation actuator ♦IJ37, IJ38,      IJ39, IJ40          ♦High efficiency  ♦IJ41          ♦CMOS compatible voltages          and currents          ♦Standard MEMS processes          can be used          ♦Easy extension from single          nozzles to pagewidth print          heads        High CTE A material with a very high ♦High force can be      generated ♦Requires special material (e.g. PTFE) .diamond-s       olid.IJ09, IJ17, IJ18, IJ20        thermoelastic coefficient of thermal expansion ♦PTFE is      a candidate for low ♦Requires a PTFE deposition process,      ♦IJ21, IJ22, IJ23, IJ24        actuator (CTE) such as dielectric constant which is not yet standard      in ULSI fabs ♦IJ27, IJ28, IJ29, IJ30         polytetrafluoroethylene (PTFE) is insulation in ULSI ♦PT       FE deposition cannot be followed ♦IJ31, IJ42, IJ43, IJ44         used. As high CTE materials are ♦Very low power with      high temperature (above 350°       C.)                                    usually non-conductive, a heater        consumption processing         fabricated from a conductive ♦Many ink types can be      used ♦Pigmented inks may be infeasible, as         material is incorporated. A 50 μm ♦Simple planar      fabrication pigment particles may jam the bend         long PTFE bend actuator with ♦Small chip area required      for actuator         polysilicon heater and 15 mW power each actuator         input can provide 180 μN force and ♦Fast operation          10 μm deflection. Actuator motions ♦High efficiency         include: CMOS compatible voltages         1) Bend and currents         2) Push ♦Easy extension from single         3) Buckle nozzles to pagewidth print         4) Rotate heads        Conductive A polymer with a high coefficient of ♦High      force can be generated ♦Requires special materials      ♦IJ24        polymer thermal expansion (such as PTFE) is ♦Very low      power development (High CTE conductive        thermoelastic doped with conducting substances to consumption polymer)        actuator. increase its conductivity to about 3 ♦Many ink        types can be used ♦Requires a PTFE deposition process,          orders of magnitude below that of ♦Simple planar      fabrication which is not yet standard in ULSI fabs         copper. The conducting polymer ♦Small chip area      required for ♦PTFE deposition cannot be followed         expands when resistively heated. each actuator with high temperature      (above 350°       C.)                                                     Examples of      conducting dopants ♦Fast operation processing         include: ♦High efficiency ♦Evaporation      and CVD deposition         1) Carbon nanotubes ♦CMOS compatible voltages techniques        cannot be used         2) Metal fibers and currents ♦Pigmented inks may be      infeasible, as         3) Conductive polymers such as ♦Easy extension from      single pigment particles may jam the bend         doped polythiophene nozzles to pagewidth print actuator         4) Carbon granules heads        Shape memory A shape memory alloy such as TiNi ♦High      force is available ♦Fatigue limits maximum number of      ♦IJ26        alloy (also known as Nitinol - Nickel (stresses of hundreds of cycles         Titanium alloy developed at the MPa) ♦Low strain (1%)      is required to extend         Naval Ordnance Laboratory) is ♦Large strain is available        fatigue resistance         thermally switched between its weak (more than 3%) ♦Cycl       e rate limited by heat removal         martensitic state and its high ♦High corrosion resistanc       e ♦Requires unusual materials (TiNi)         stiffness austenic state. The shape of ♦Simple construct       ion ♦The latent heat of transformation must         the actuator in its martensitic state is ♦Easy extension        from single be provided         deformed relative to the austenic nozzles to pagewidth print .diamond-       solid.High current operation         shape. The shape change causes heads ♦Requires pre-stres       sing to distort the         ejection of a drop. ♦Low voltage operation martensitic      state        Linear Linear magnetic actuators include ♦Linear      Magnetic actuators ♦Requires unusual semiconductor      ♦IJ12        Magnetic the Linear Induction Actuator (LIA), can he constructed with      materials such as soft magnetic alloys        Actuator Linear Permanent Magnet high thrust, long travel, and (e.g.      CoNiFe [1])         Synchronous Actuator (LPMSA), high efficiency using planar .diamond-so       lid.Some varieties also require permanent         Linear Reluctance Synchronous semiconductor fabrication magnetic      materials such as         Actuator (LRSA), Linear Switched techniques Neodymium iron boron      (NdFeB)         Reluctance Actuator (LSRA), and ♦Long actuator travel      is ♦Requires complex multi-phase drive         the Linear Stepper Actuator (LSA). available circuitry          ♦Medium force is available ♦High current        operation          ♦Low voltage operation        BASIC OPERATION MODE        Operational        mode        Actuator This is the simplest mode of ♦Simple operation      ♦Drop repetition rate is usually limited ♦The       rmal inkjet        directly operation: the actuator directly ♦No external      fields required to less than 10 KHz. However, this is ♦Piez       oelectric inkjet        pushes ink supplies sufficient kinetic energy to ♦Satelli       te drops can be not fundamental to the method, but is ♦IJ0       1, IJ02, IJ03, IJ04         expel the drop. The drop must have a avoided if drop velocity is      related to the refill method normally ♦IJ05, IJ06, IJ07,      IJ09         sufficient velocity to overcome the less than 4 m/s used .diamond-soli       d.IJ11, IJ12, IJ14, IJ16         surface tension ♦Can be efficient, depending .diamond-so       lid.All of the drop kinetic energy must be ♦IJ20, IJ22,      IJ23, IJ24          upon the actuator used provided by the actuator ♦IJ25,        IJ26, IJ27, IJ28           ♦Satellite drops usually form if drop ♦I       J29, IJ30, IJ31, IJ32           velocity is greater than 4.5 m/s ♦IJ33, IJ34, IJ35,      IJ36            ♦IJ37, IJ38, IJ39, IJ40            ♦IJ41, IJ42, IJ43, IJ44        Proximity The drops to be printed are selected ♦Very      simple print head ♦Requires close proximity between the      ♦Silverbrook, EP 0771         by some manner (e.g. thermally fabrication can be used print head and        the print media or 658 A2 and related         induced surface tension reduction of ♦The drop selection        means transfer roller patent applications         pressurized ink). Selected drops are does not need to provide the      ♦May require two print heads printing         separated from the ink in the nozzle energy required to separate      alternate rows of the image         by contact with the print medium or the drop from the nozzle .diamond-       solid.Monolithic color print heads are         a transfer roller.  difficult        Electrostatic The drops to be printed are selected ♦Very        simple print head ♦Requires very high electrostatic      field ♦Silverbrook, EP 077        pull on ink by some manner (e.g. thermally fabrication can be used      ♦Electrostatic field for small nozzle 658 A2 and related          induced surface tension reduction of ♦The drop      selection means sizes is above air breakdown patent applications                pressurized ink). Selected drops are does not need to provide      the ♦Electrostatic field may attract dust ♦To       ne-Jet         separated from the ink in the nozzle energy required to separate             by a strong electric field. the drop from the nozzle        Magnetic pull The drops to be printed are selected ♦Very        simple print head ♦Requires magnetic ink ♦S       ilverbrook, EP 0771        on ink by some manner (e.g. thermally fabrication can be used .diamond-       solid.Ink colors other than black are difficult 658 A2 and related             induced surface tension reduction of ♦The drop      selection means ♦Requires very high magnetic fields patent        applications         pressurized ink). Selected drops are does not need to provide the            separated from the ink in the nozzle energy required to separate          by a strong magnetic held acting on the drop from the nozzle                the magnetic ink.        Shutter The actuator moves a shutter to ♦High speed (>50        KHz) ♦Moving parts are required ♦IJ13,      IJ17, IJ21         block ink flow to the nozzle. The ink operation can be achieved      ♦Requires ink pressure modulator         pressure is pulsed at a multiple of the due to reduced refill time      ♦Friction and wear must be considered         drop ejection frequency. ♦Drop timing can be very      ♦Stiction is possible          accurate          ♦The actuator energy can be          very low        Shuttered grill The actuator moves a shutter to ♦Actuator       s with small travel ♦Moving parts are required .diamond-so       lid.IJ08, IJ15, IJ18, IJ19         block ink flow through a grill to the can be used ♦Requi       res ink pressure modulator         nozzle. The shutter movement need ♦Actuators with small        force ♦Friction and wear must be considered         only be equal to the width of the grill can be used ♦Sti       ction is possible         holes. ♦High speed (>50 KHz)          operation can be achieved        Pulsed A pulsed magnetic field attracts an ♦Extremely      low energy ♦Requires an external pulsed magnetic .diamond-s       olid.IJ10        magnetic pull `ink pusher` at the drop ejection operation is possible      field        on ink pusher frequency. An actuator controls a ♦No heat        dissipation ♦Requires special materials for both the            catch, which prevents the ink pusher problems actuator and the ink        pusher         from moving when a drop is not to  ♦Complex construction         be ejected.        AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES)        Auxiliary        Mechanism        None The actuator directly fires the ink ♦Simplicity of      construction ♦Drop ejection energy must be supplied      ♦Most inkjets,         drop, and there is no external field or ♦Simplicity of      operation by individual nozzle actuator including         other mechanism required ♦Small physical size  piezoelec       tric and            thermal bubble.            ♦IJ01-IJ07, IJ09, IJ11            ♦IJ12, IJ14, IJ20, IJ22            ♦IJ23-IJ45        Oscillating ink The ink pressure oscillates, ♦Oscillating        ink pressure can ♦Requires external ink pressure      ♦Silverbrook, EP 0771        pressure providing much of the drop ejection provide a refill pulse,      oscillator 658 A2 and related        (including energy. The actuator selects which allowing higher operating        ♦Ink pressure phase and amplitude must patent application       s        acoustic drops are to be fired by selectively speed be carefully      controlled ♦IJ08, IJ13, IJ15, IJ17        stimulation) blocking or enabling nozzles. The ♦The      actuators may operate ♦Acoustic reflections in the ink      chamber ♦IJ18, IJ19, IJ21         ink pressure oscillation may he with much tower energy must be      designed for         achieved by vibrating the print head, ♦Acoustic lenses      can be used         or preferably by an actuator in the to focus the sound on the                ink supply. nozzles        Media The print head is placed in close ♦Low power      ♦Precision assembly required ♦Silverbrook,      EP 0771        proximity proximity to the print medium. ♦High accuracy      ♦Paper fibers may cause problems 658 A2 and related               Selected drops protrude from the ♦Simple print      head ♦Cannot print on rough substrates patent applications         print head further than unselected construction         drops, and contact the print medium.         The drop soaks into the medium fast         enough to cause drop separation.        Transfer roller Drops are printed to a transfer roller ♦H       igh accuracy ♦Bulky ♦Silverbrook, EP 0771          instead of straight to the print ♦Wide range of print      ♦Expensive 658 A2 and related         medium. A transfer roller can also be substrates can be used .diamond-       solid.Complex construction patent applications         used for proximity drop separation. ♦Ink can be dried      on the  ♦Tektronix hot melt          transfer roller  piezoelectric inkjet            ♦Any of the IJ series        Electrostatic An electric field is used to accelerate ♦Lo       w power ♦Field strength required for separation .diamond-s       olid.Silverbrook, EP 0771         selected drops towards the print ♦Simple print head of      small drops is near or above air 658 A2 and related         medium. constriction breakdown patent applications            ♦Tone-Jet        Direct A magnetic field is used to accelerate ♦Low power        ♦Requires magnetic ink ♦Silverbrook, EP      0771        magnetic field selected drops of magnetic ink ♦Simple      print head ♦Requires strong magnetic field 658 A2 and      related         towards the print medium. construction  patent applications        Cross The print head is placed in a constant ♦Does not      require magnetic ♦Requires external magnet ♦I       J06, IJ16        magnetic field magnetic field. The Lorenz force in a materials to be      integrated in ♦Current densities may be high,         current carrying wire is used to move the print head resulting in      electromigration problems         the actuator. manufacturing process        Pulsed A pulsed magnetic field is used to ♦Very low      power operation ♦Complex print head construction .diamond-s       olid.IJ10        magnetic field cyclically attract a paddle, which is possible.      ♦Magnetic materials required in print         pushes on the ink. A small actuator ♦Small print head      size head         moves a catch, which selectively         prevents the paddle from moving.        ACTUATOR AMPLIFICATION OR MODIFICATION METHOD        Actuator        amplification        None No actuator mechanical ♦Operational simplicity      ♦Many actuator mechanisms have ♦Thermal      Bubble         amplification is used. The actuator  insufficient travel, or insuffici       ent force, Inkjet         directly drives the drop ejection  to efficiently drive the drop      ejection ♦IJ01, IJ02, IJ06, IJ07         process.  process ♦IJ16, IJ25, IJ26        Differential An actuator material expands more ♦Provides        greater travel in a ♦High stresses are involved .diamond-       solid.Piezoelectric        expansion on one side than on the other. The reduced print head area      ♦Care must be taken that the materials ♦IJ03,        IJ09, IJ17-IJ24        bend actuator expansion may be thermal, ♦The bend      actuator converts do not delaminate ♦IJ27, IJ29-IJ39 IJ42,         piezoelectric, magnetostrictive, or a high force low travel .diamond-s       olid.Residual bend resulting from high ♦IJ43, IJ44               other mechanism. actuator mechanism to high temperature or high        stress during          travel, lower force formation          mechanism.        Transient bend A trilayer bend actuator where the ♦Very      good temperature ♦High stresses are involved .diamond-solid       .IJ40, IJ41        actuator two outside layers are identical. This stability .diamond-soli       d.Care must be taken that the materials         cancels bend due to ambient ♦High speed, as a new drop      do not delaminate         temperature and residual stress. The can be fired before heat                actuator only responds to transient dissipates         heating of one side or the other. ♦Cancels residual      stress of          formation        Actuator stack A series of thin actuators are stacked. ♦I       ncreased travel ♦Increased fabrication complexity      ♦Some piezoelectric         This can be appropriate where ♦Reduced drive voltage      ♦Increased possibility of short circuits ink jets         actuators require high electric field  due to pinholes ♦       IJ04         strength, such as electrostatic and         piezoelectric actuators.        Multiple Multiple smaller actuators are used ♦Increases      the force available ♦Actuator forces may not add linearly,        ♦IJ12, IJ13, IJ18, IJ20        actuators simultaneously to move the ink. from an actuator reducing      efficiency ♦IJ22, IJ28, IJ42, IJ43         Each actuator need provide only a ♦Multiple actuators      can be         portion of the force required. positioned to control ink          flow accurately        Linear Spring A linear spring is used to transform a ♦Mat       ches low travel actuator ♦Requires print head area for      the spring ♦IJ15         motion with small travel and high with higher travel         force into a longer travel, lower force requirements         motion. ♦Non-contact method of          motion transformation        Reverse spring The actuator loads a spring. When ♦Better        coupling to the ink ♦Fabrication complexity .diamond-soli       d.IJ05, IJ11         the actuator is tuned off, the spring  ♦High stress in      the spring         releases. This can reverse the         force/distance curve of the actuator         to make it compatible with the         force/time requirements of the drop         ejection.        Coiled A bend actuator is coiled to provide ♦Increases      travel ♦Generally restricted to planar ♦IJ17,        IJ21, IJ34, IJ35        actuator greater travel in a reduced chip area. ♦Reduces        chip area implementations due to extreme          ♦Planar implementations are fabrication difficulty in      other          relatively easy to fabricate. orientations.        Flexure bend A bend actuator has a small region ♦Simple      means of increasing ♦Care must be taken not to exceed the      ♦IJ10, IJ19, IJ33        actuator near the fixture point, which flexes travel of a bend      actuator elastic limit in the flexure area         much more readily than the  ♦Stress distribution is      very uneven         remainder of the actuator. The  ♦Difficult to accurately        model with         actuator flexing is effectively  finite element analysis         converted from an even coiling to an         angular bend, resulting in greater         travel of the actuator tip.        Gears Gears can be used to increase travel ♦Low force,      low travel ♦Moving parts are required ♦IJ13         at the expense of duration. Circular actuators can be used .diamond-so       lid.Several actuator cycles are required         gears, rack and pinion, ratchets, and ♦Can be fabricated        using ♦More complex drive electronics         other gearing methods can be used. standard surface MEMS .diamond-soli       d.Complex construction          processes ♦Friction, friction, and wear are possible         Catch The actuator controls a small catch. ♦Very low      actuator energy ♦Complex construction ♦IJ10         The catch either enables or disables ♦Very small      actuator size ♦Requires external force         movement of an ink pusher that is  ♦Unsuitable for      pigmented inks         controlled in a bulk manner.        Buckle plate A buckle plate can be used to change ♦Very      fast movement ♦Must stay within elastic limits of the      ♦S. Hirata et al, "An         a slow actuator into a fast motion. It achievable materials for long      device life Ink-jet Head . . . ",         can also convert a high force, low  ♦High stresses      involved Proc. IEEE MEMS,         travel actuator into a high travel,  ♦Generally high      power requirement Feb. 1996, pp 418-         medium force motion.   423.            ♦IJ18, IJ27        Tapered A tapered magnetic pole can increase ♦Linearizes        the magnetic ♦Complex construction ♦IJ14         magnetic pole travel at the expense of force. force/distance curve          Lever A lever and fulcrum is used to ♦Matches low      travel actuator ♦High stress around the fulcrum .diamond-so       lid.IJ32, IJ36, IJ37         transform a motion with small travel with higher travel         and high force into a motion with requirements         longer travel and lower force. The ♦Fulcrum area has no        linear         lever can also reverse the direction of movement, and can be used            travel. for a fluid seal        Rotary The actuator is connected to a rotary ♦High      mechanical advantage ♦Complex construction ♦I       J28        impeller impeller. A small angular deflection ♦The ratio        of force to travel ♦Unsuitable for pigmented inks               of the actuator results in a rotation of of the actuator can be         the impeller vanes, which push the matched to the nozzle         ink against stationary vanes and out requirements by varying the             of the nozzle. number of impeller vanes        Acoustic lens A refractive or diffractive (e.g. zone ♦No        moving parts ♦Large area required ♦1993      Hadimioglu et         plate) acoustic lens is used to  ♦Only relevant for      acoustic ink jets al, EUP 550, 192         concentrate sound waves.   ♦1993 Elrod et al, EUP                 572,220        Sharp A sharp point is used to concentrate ♦Simple      construction ♦Difficult to fabricate using standard      ♦Tone-jet        conductive an electrostatic field.  VLSL processes for a surface      ejecting        point   ink-jet           ♦Only relevant for electrostatic ink jets        ACTUATOR MOTION        Actuator        motion        Volume The volume of the actuator changes, ♦Simple      construction in the ♦High energy is typically required to      ♦Hewlett-Packard        expansion pushing the ink in all directions. case of thermal ink jet      achieve volume expansion. This leads Thermal Inkjet           to thermal stress, cavitation, and ♦Canon Bubblejet            kogation in thermal ink jet           implementations        Linear, normal The actuator moves in a direction ♦Efficie       nt coupling to ink ♦High fabrication complexity may be      ♦IJ01, IJ02, IJ04, IJ07        to chip surface normal to the print head surface. The drops ejected      normal to the required to achieve perpendicular ♦IJ11,      IJ14         nozzle is typically in the line of surface motion         movement.        Linear, parallel The actuator moves parallel to the ♦Suit       able for planar ♦Fabrication complexity ♦IJ1       2, IJ13, IJ15, IJ33,        to chip surface print head surface. Drop ejection fabrication      ♦Friction ♦IJ34, IJ35, IJ36         may still be normal to the surface.  ♦Stiction        Membrane An actuator with a high force but ♦The effective        area of the ♦Fabrication complexity ♦1982      Hawkins U.S. Pat. No.        push small area is used to push a stiff actuator becomes the .diamond-s       olid.Actuator size 4,459,601         membrane that is in contact with the membrane area ♦Diff       iculty of integration in a VLSI         ink.  process        Rotary The actuator causes the rotation of ♦Rotary      levers may be used ♦Device complexity ♦IJ05,        IJ08, IJ13, IJ28         some element, such a grill or to increase travel ♦May      have friction at a pivot point         impeller ♦Small chip area          requirements        Bend The actuator bends when energized. ♦A very small      change in ♦Requires the actuator to be made from .diamond-s       olid.1970 Kyser et al U.S. Pat. No.         This may be due to differential dimensions can be at least two      distinct layers, or to have a 3,946,398         thermal expansion, piezoelectric converted to a large motion. thermal        difference across the actuator ♦1973 Stemme U.S. Pat.      No.         expansion, magnetostriction, or other   ♦3,747,120             form of relative dimensional change.   ♦IJ03, IJ09,        IJ10, IJ19            ♦IJ23, IJ24, IJ25, IJ29            ♦IJ30, IJ31, IJ33, IJ34            ♦IJ35        Swivel The actuator swivels around a central ♦Allows      operation where the ♦Inefficient coupling to the ink      motion ♦IJ06         pivot. This motion is suitable where net linear force on the         there are opposite forces applied to paddle is zero         opposite sides of the paddle, e.g. ♦Small chip area            Lorenz force. requirements        Straighten The actuator is normally bent, and ♦Can be      used with shape ♦Requires careful balance of stresses to      ♦IJ26, IJ32         straightens when energized. memory alloys where the ensure that the      quiescent bend is          austenic phase is planar accurate        Double bend The actuator bends in one direction ♦One      actuator can be used to ♦Difficult to make the drops      ejected by ♦IJ36, IJ37, IJ38         when one element is energized, and power two nozzles. both bend      directions identical.         bends the other way when another ♦Reduced chip size.      ♦A small efficiency loss compared to         element is energized. ♦Not sensitive to ambient      equivalent single bend actuators.          temperature        Shear Energizing the actuator causes a ♦Can increase the        effective ♦Not readily applicable to other actuator      ♦1985 Fishbeck U.S. Pat. No.         shear motion in the actuator material. travel of piezoelectric      mechanisms 4,584,590          actuators        Radial The actuator squeezes an ink ♦Relatively easy to      fabricate ♦High force required ♦1970 Zoltan      U.S. Pat. No.        constriction reservoir, forcing ink from a single nozzles from glass      ♦Inefficient 3,683,212         constricted nozzle. tubing as macroscopic ♦Difficult to        integrate with VLSI          structures processes        Coil/uncoil A coiled actuator uncoils or coils ♦Easy to      fabricate as a planar ♦Difficult to fabricate for non-plana       r ♦IJ17, IJ21, IJ34, IJ35         more tightly. The motion of the free VLSI process devices         end of the actuator ejects the ink. ♦Small area      required, ♦Poor out-of-plane stiffness          therefore low cost        Bow The actuator bows (or buckles) in the ♦Can increase      the speed of ♦Maximum travel is constrained ♦       IJ16, IJ18, IJ27         middle when energized. travel ♦High force required              ♦Mechanically rigid        Push-Pull Two actuators control a shutter. One ♦The      structure is pinned at ♦Not readily suitable for inkjets      which ♦IJ18         actuator pulls the shutter, and the both ends, so has a high directly        push the ink         other pushes it. out-of-plane rigidity        Curl inwards A set of actuators curl inwards to ♦Good      fluid flow to the ♦Design complexity ♦IJ20,      IJ42         reduce the volume of ink that they region behind the actuator                enclose. increases efficiency        Curl outwards A set of actuators curl outwards, ♦Relative       ly simple ♦Relatively large chip area ♦IJ43         pressurizing ink in a chamber construction         surrounding the actuators, and         expelling ink from a nozzle in the         chamber.        Iris Multiple vanes enclose a volume of ♦High efficiency        ♦High fabrication complexity ♦IJ22                ink. These simultaneously rotate, ♦Small chip      area ♦Not suitable for pigmented inks         reducing the volume between the         vanes.        Acoustic The actuator vibrates at a high ♦The actuator      can be ♦Large area required for efficient ♦19       93 Hadimioglu et        vibration frequency. physically distant from the operation at useful      frequencies al, EUP 550,192          ink ♦Acoustic coupling and crosstalk ♦199       3 Elrod et al, EUP           ♦Complex drive circuitry. 572,220           ♦Poor control of drop volume and           position        None In various ink jet designs the actuator ♦No moving      parts ♦Various other tradeoffs are required to .diamond-sol       id.Silverbrook, EP 0771         does not move.  eliminate moving parts 658 A2 and related            patent applications            ♦Tone-jet        NOZZLE REFILL METHOD        Nozzle refill        method        Surface After the actuator is energized, it ♦Fabrication        simplicity ♦Low speed ♦Thermal inkjet            tension typically returns rapidly to its normal ♦Oper       ational simplicity ♦Surface tension force relatively      small ♦Piezoelectric inkjet         position. This rapid return sucks in  compared to actuator force      ♦IJ01-IJ07, IJ10-IJ14         air through the nozzle opening. The  ♦Long refill time      usually dominates the ♦IJ16, IJ20, IJ22-IJ45         ink surface tension at the nozzle then  total repetition rate                exerts a small force restoring the         meniscus to a minimum area.        Shuttered Ink to the nozzle chamber is ♦High speed      ♦Requires common ink pressure ♦IJ08, IJ13,      IJ15, IJ17        oscillating ink provided at a pressure that oscillates ♦L       ow actuator energy, as the oscillator ♦IJ18, IJ19, IJ21         pressure at twice the drop ejection frequency. actuator need only      open or ♦May not be suitable for pigmented inks         When a drop is to be ejected, the close the shutter, instead of              shutter is opened for 3 half cycles: ejecting the ink drop              drop ejection, actuator return, and         refill.        Refill actuator After the main actuator has ejected a ♦Hi       gh speed, as the nozzle is ♦Requires two independent      actuators per ♦IJ09         drop a second (refill) actuator is actively refilled nozzle         energized. The refill actuator pushes         ink into the nozzle chamber. The         refill actuator returns slowly, to         prevent its return from emptying the         chamber again.        Positive ink The ink is held a slight positive ♦High      refill rate, therefore a ♦Surface spill must be prevented      ♦Silverbrook, EP 0771        pressure pressure. After the ink drop is high drop repetition rate is      ♦Highly hydrophobic print head 658 A2 and related         ejected, the nozzle chamber fills possible surfaces are required      patent applications         quickly as surface tension and ink   ♦Alternative for:         pressure both operate to refill the   ♦IJ01-IJ07,      IJ10-IJ14         nozzle.   ♦IJ16, IJ20, IJ22-IJ45        METHOD OF RESTRICTING BACK-FLOW THROUGH INLET        Inlet back-flow        restriction        method        Long inlet The ink inlet channel to the nozzle ♦Design      simplicity ♦Restricts refill rate ♦Thermal      inkjet        channel chamber is made long and relatively ♦Operational        simplicity ♦May result in a relatively large chip      ♦Piezoelectric inkjet         narrow, relying on viscous drag to ♦Reduces crosstalk      area ♦IJ42, IJ43         reduce inlet back-flow.  ♦Only partially effective            Positive ink The ink is under a positive pressure, ♦D       rop selection and ♦Requires a method (such as a nozzle      ♦Silverbrook, EP 0771        pressure so that in the quiescent state some of separation forces can      be rim or effective hydrophobizing, or 658 A2 and related         the ink drop already protrudes from reduced both) to prevent flooding        of the patent applications         the nozzle. ♦Fast refill time ejection surface of the      print head. ♦possible operation of         This reduces the pressure in the   the following:         nozzle chamber which is required to   ♦IJ01-IJ07,      IJ09-IJ12         eject a certain volume of ink. The   ♦IJ14, IJ16, IJ20,        IJ22,         reduction in chamber pressure results   ♦IJ23-IJ34,      IJ36-IJ41         in a reduction in ink pushed out   ♦IJ44         through the inlet.        Baffle One or more baffles are placed in the ♦The refill        rate is not as ♦Design complexity ♦HP      Thermal Ink Jet         inlet ink flow. When the actuator is restricted as the long inlet      ♦May increase fabrication complexity ♦Tektron       ix         energized, the rapid ink movement method. (e.g. Tektronix hot melt      Piezoelectric piezoelectric ink jet         creates eddies which restrict the flow ♦Reduces      crosstalk print heads).         through the inlet. The slower refill         process is unrestricted, and does not         result in eddies.        Flexible flap In this method recently disclosed by ♦Signi       ficantly reduces back- ♦Not applicable to most inkjet      ♦Canon        restricts inlet Canon, the expanding actuator flow for edge-shooter      configurations         (bubble) pushes on a flexible flap thermal ink jet devices .diamond-so       lid.Increased fabrication complexity         that restricts the inlet.  ♦Inelastic deformation of      polymer flap           results in creep over extended use        Inlet filter A filter is located between the ink ♦Additio       nal advantage of ink ♦Restricts refill rate .diamond-solid       .IJ04, IJ12, IJ24,         inlet and the nozzle chamber. The filtration ♦May      result in complex construction ♦IJ29, IJ30         filter has a multitude of small holes ♦Ink filter may      be fabricated         or slots, restricting ink flow. The with no additional process               filter also removes particles which steps         may block the nozzle.        Small inlet The ink inlet channel to the nozzle ♦Design      simplicity ♦Restricts refill rate ♦IJ02,      IJ37, IJ44        compared to chamber has a substantially smaller  ♦May      result in a relatively large chip        nozzle cross section than that of the nozzle,  area         resulting in easier ink egress out of  ♦Only partially      effective         the nozzle than out of the inlet.        Inlet shutter A secondary actuator controls the ♦Increase       s speed of the ink- ♦Requires separate refill actuator      and ♦IJ09         position of a shutter, closing off the jet print head operation drive        circuit         ink inlet when the main actuator is         energized.        The inlet is The method avoids the problem of ♦Back-flow        problem is ♦Requires careful design to minimize .diamond-       solid.IJ01, IJ03, IJ05, IJ06        located behind inlet back-flow by arranging the ink- eliminated the      negative pressure behind the paddle ♦IJ07, IJ10, IJ11,      IJ14        the ink- pushing surface of the actuator   ♦IJ16, IJ22,      IJ23, IJ25        pushing between the inlet and the nozzle.   ♦IJ28, IJ31,        IJ32, IJ33        surface    ♦IJ34, IJ35, IJ36, IJ39            ♦IJ40, IJ41        Part of the The actuator and a wall of the ink ♦Significa       nt reductions in ♦Small increase in fabrication .diamond-s       olid.IJ07, IJ20, IJ26, IJ38        actuator chamber are arranged so that the back-flow can be achieved      complexity        moves to shut motion of the actuator closes off the ♦Comp       act designs possible        off the inlet inlet.        Nozzle In some configurations of ink jet, ♦Ink back-flow        problem is ♦None related to ink back-flow on .diamond-sol       id.Silverbrook, EP 0771        actuator does there is no expansion or movement eliminated actuation      658 A2 and related        not result in of an actuator which may cause ink   patent applications        ink back-flow back-flow through the inlet.   ♦Valve-jet            ♦Tone-jet            ♦IJ08, IJ13, IJ15, IJ17            ♦IJ18, IJ19, IJ21        NOZZLE CLEARING METHOD        Nozzle        Clearing        method        Normal nozzle All of the nozzles are fired ♦No added      complexity on the ♦May not be sufficient to displace dried        ♦Most ink jet systems        firing periodically, before the ink has a print head ink .diamond-solid       .IJ01-IJ07, IJ09-IJ12         chance to dry. When not in use the   ♦IJ14, IJ16, IJ20,        IJ22         nozzles are sealed (capped) against   ♦IJ23-IJ34,      IJ36-IJ45         air.         The nozzle firing is usually         performed during a special clearing         cycle, after first moving the print         head to a cleaning station.        Extra power to In systems which heat the ink, but do ♦Can        be highly effective if ♦Requires higher drive voltage      for ♦Silverbrook, EP 0771        ink heater not boil it under normal situations, the heater is adjacent        to the clearing 658 A2 and related         nozzle clearing can be achieved by nozzle ♦May require      larger drive transistors patent applications         over-powering the heater and boiling         ink at the nozzle.        Rapid The actuator is fired in rapid ♦Does not require      extra drive ♦Effectiveness depends substantially .diamond-s       olid.May be used with:        succession of succession. In some configurations, circuits on the      print head upon the configuration of the inkjet ♦IJ01-IJ07,        IJ09-IJ11        actuator this may cause heat build-up at the ♦Can be      readily controlled nozzle ♦IJ14, IJ16, IJ20, IJ22        pulses nozzle which boils the ink, clearing and initiated by digital      logic  ♦IJ23-1125, IJ27-IJ34         the nozzle. In other situations, it may   ♦IJ36-IJ45           cause sufficient vibrations to         dislodge clogged nozzles.        Extra power to Where an actuator is not normally ♦A      simple solution where ♦Not suitable where there is a hard      limit ♦May be used with:        ink pushing driven to the limit of its motion, applicable to actuator      movement ♦IJ03, IJ09, IJ16, IJ20        actuator nozzle clearing may be assisted by   ♦IJ23,      IJ24, IJ25, IJ27         providing an enhanced drive signal   ♦IJ29, IJ30, IJ31,        IJ32         to the actuator.   ♦IJ39, IJ40, IJ41, IJ42            ♦IJ43, IJ44, IJ45        Acoustic An ultrasonic wave is applied to the ♦A high      nozzle clearing ♦High implementation cost if system      ♦IJ08, IJ13, IJ15, IJ17        resonance ink chamber. This wave is of an capability can be achieved      does not already include an acoustic ♦IJ18, IJ19, IJ21            appropriate amplitude and frequency ♦May be implement       ed at actuator         to cause sufficient force at the nozzle very low cost in systems             to clear blockages. This is easiest to which already include             achieve if the ultrasonic wave is at a acoustic actuators                resonant frequency of the ink cavity.        Nozzle A microfabricated plate is pushed ♦Can clear      severely clogged ♦Accurate mechanical alignment is      ♦Silverbrook, EP 0771        clearing plate against the nozzles. The plate has a nozzles required      658 A2 and related         post for every nozzle. The array of  ♦Moving parts are      required patent applications         posts  ♦There is risk of damage to the nozzles           ♦Accurate fabrication is required        Ink pressure The pressure of the ink is ♦May be effective        where ♦Requires pressure pump or other ♦May        be used with all        pulse temporarily increased so that ink other methods cannot be      pressure actuator IJ series ink         streams from all of the nozzles. This used ♦Expensive          may be used in conjunction with  ♦Wasteful of ink             actuator energizing.        Print head A flexible `blade`       is wiped across the ♦Effective for planar print .diamond-s       olid.Difficult to use if print head surface is ♦Many ink      jet systems        wiper print head surface. The blade is head surfaces non-planar or      very fragile         usually fabricated from a flexible ♦Low cost .diamond-so       lid.Requires mechanical parts         polymer, e.g. rubber or synthetic  ♦Blade can wear out      in high volume         elastomer.  print systems        Separate ink A separate heater is provided at the ♦Can      be effective where ♦Fabrication complexity ♦C       an be used with        boiling heater nozzle although the normal drop e- other nozzle      clearing  many IJ series ink         ection mechanism does not require it. methods cannot be used  jets           The heaters do not require individual ♦Can be      implemented at no         drive circuits, as many nozzles can additional cost in some         be cleared simultaneously, and no inkjet configurations         imaging is required.        NOZZLE PLATE CONSTRUCTION        Nozzle plate        construction        Electroformed A nozzle plate is separately ♦Fabrication      simplicity ♦High temperatures and pressures are .diamond-so       lid.Hewlett Packard        nickel fabricated from electroformed nickel,  required to bond nozzle      plate Thermal Inkjet         and bonded to the print head chip.  ♦Minimum thickness      constraints           ♦Differential thermal expansion        Laser ablated Individual nozzle holes are ablated ♦No      masks required ♦Each hole must be individually formed      ♦Canon Bubblejet        or drilled by an intense UV laser in a nozzle ♦Can be      quite fast ♦Special equipment required ♦1988        Sercel et al.,        polymer plate, which is typically a polymer ♦Some      control over nozzle ♦Slow where there are many thousands      SPIE, Vol. 998         such as polyimide or polysulphone profile is possible of nozzles per      print head Excimer Beam          ♦Equipment required is ♦May produce thin        burrs at exit holes Applications, pp. 76-          relatively low cost  83            ♦1993 Watanabe et al.,            U.S. Pat. No. 5,208,604        Silicon micro- A separate nozzle plate is ♦High accuracy        is attainable ♦Two part construction ♦K.      Bean, IEEE        machined micromachined from single crystal  ♦High cost      Transactions on         silicon, and bonded to the print head  ♦Requires      precision alignment Electron Devices,         wafer.  ♦Nozzles may be clogged by adhesive Vol. ED-25,        No. 10,            1978, pp 1185-1195            ♦Xerox 1990 Hawkin            et al., U.S. Pat. No. 4,899,181        Glass Fine glass capillaries are drawn from ♦No expensive        equipment ♦Very small nozzle sizes are difficult to      ♦1970 Zoltan U.S. Pat. No.        capillaries glass tubing. This method has been required form 3,683,212         used for making individual nozzles, ♦Simple to make      single ♦Not suited for mass production         but is difficult to use for bulk nozzles         manufacturing of print heads with         thousands of nozzles.        Monolithic, The nozzle plate is deposited as a ♦High      accuracy (<1 μm) ♦Requires sacrificial layer under the      ♦Silverbrook, EP 0771        surface micro- layer using standard VLSI deposition ♦Mono       lithic nozzle plate to form the nozzle 658 A2 and related        machined techniques. Nozzles are etched in the ♦Low cost        chamber patent applications        using VLSI nozzle plate using VLSI lithography ♦Existing        processes can be ♦Surface may be fragile to the touch      ♦IJ01, IJ02, IJ04, IJ11        lithographic and etching. used  ♦IJ12, IJ17, IJ18, IJ20        processes    ♦IJ22, IJ24, IJ27, IJ28            ♦IJ29, IJ30, IJ31, IJ32            ♦IJ33, IJ34, IJ36, IJ37            ♦IJ38, IJ39, IJ40, IJ41            ♦IJ42, IJ43, IJ44        Monolithic, The nozzle plate is a buried etch stop ♦High        accuracy (<1 μm) ♦Requires long etch times .diamond-so       lid.IJ03, IJ05, IJ06, IJ07        etched in the wafer. Nozzle chambers are ♦Monolithic      ♦Requires a support wafer ♦IJ08, IJ09, IJ10,        IJ13        through etched in the front of the wafer, and ♦Low cost        ♦IJ14, IJ15, IJ16, IJ19        substrate the wafer is thinned from the back ♦No      differential expansion  ♦IJ21, IJ23, IJ25, IJ26         side. Nozzles are then etched in the         etch stop layer.        No nozzle Various methods have been tried to ♦No nozzles        to become ♦Difficult to control drop position .diamond-so       lid.Ricoh 1995 Sekiya et        plate eliminate the nozzles entirely, to clogged accurately al U.S.      Pat. No. 5,412,413         prevent nozzle clogging. These  ♦Crosstalk problems      ♦1993 Hadimioglu et         include thermal bubble mechanisms   al EUP 550,192         and acoustic lens mechanisms   ♦1993 Elrod et al EUP              572,220        Trough Each drop ejector has a trough ♦Reduced manufactur       ing ♦Drop firing direction is sensitive to ♦       IJ35         through which a paddle moves. complexity wicking.         There is no nozzle plate. ♦Monolithic        Nozzle slit The elimination of nozzle holes and ♦No      nozzles to become ♦Difficult to control drop position      ♦1989 Saito et al U.S. Pat. No.        instead of replacement by a slit encompassing clogged accurately      4,799,068        individual many actuator positions reduces  ♦Crosstalk      problems        nozzles nozzle clogging, but increases         crosstalk due to ink surface waves        DROP EJECTION DIRECTION        Ejection        direction        Edge Ink flow is along the surface of the ♦Simple      construction ♦Nozzles limited to edge ♦Canon        Bubblejet        (`edge chip, and ink drops are ejected from ♦No silicon      etching required ♦High resolution is difficult 1979 Endo      et al GB        shooter`) the chip edge. ♦Good heat sinking via .diamond-       solid.Fast color printing requires one print patent 2,007,162          ♦substrate head per color ♦Xerox      heater-in-pit          ♦Mechanically strong  1990 Hawkins et al          ♦Ease of chip handing  U.S. Pat. No. 4,899,181                   ♦Tone-jet        Surface Ink flow is along the surface of the ♦No bulk      silicon etching ♦Maximum ink flow is severely .diamond-soli       d.Hewlett-Packard TIJ        (`roof shooter`) chip, and ink drops are ejected from required      restricted 1982 Vaught et al         the chip surface, normal to the plane ♦Silicon can make        an  U.S. Pat. No. 4,490,728         of the chip. effective heat sink  ♦IJ02, IJ11, IJ12,      IJ20          ♦Mechanical strength  ♦IJ22        Through chip, Ink flow is through the chip, and ink ♦High        ink flow ♦Requires bulk silicon etching ♦Si       lverbrook, EP 0771        forward drops are ejected from the front ♦Suitable for      pagewidth print  658 A2 and related        (`up shooter`) surface of the chip. ♦High nozzle packing         patent applications          density therefore low  ♦IJ04, IJ17, IJ18, IJ24                 manufacturing cost  ♦IJ27-IJ45        Through chip, Ink flow is through the chip, and ink ♦High        ink flow ♦Requires wafer thinning ♦IJ01,      IJ03, IJ05, IJ06        reverse drops are ejected from the rear ♦Suitable for      pagewidth print ♦Requires special handling during .diamond-       solid.IJ07, IJ08, IJ09, IJ10        (`down surface of the chip. ♦High nozzle packing      manufacture ♦IJ13, IJ14, IJ15, IJ16        shooter`)  density therefore low  ♦IJ19, IJ21, IJ23,      IJ25          manufacturing cost  ♦IJ26        Through Ink flow is through the actuator, ♦Suitable for      piezoelectric ♦Pagewidth print heads require several      ♦Epson Stylus        actuator which is not fabricated as part of the print heads thousand      connections to drive circuits ♦Tektronix hot melt         same substrate as the drive  ♦Cannot be manufactured in        standard piezoelectric ink jets         transistors.  CMOS fabs           ♦Complex assembly required        INK TYPE        Ink type        Aqueous, dye Water based ink which typically ♦Environment       ally friendly ♦Slow drying ♦Most existing      inkjets         contains: water, dye, surfactant, ♦No odor .diamond-soli       d.Corrosive ♦All IJ series ink jets         humectant, and biocide.  ♦Bleeds on paper .diamond-solid       .Silverbrook, EP 0771         Modern ink dyes have high water-  ♦May strikethrough      658 A2 and related         fastness, light fastness  ♦Cockles paper patent      applications        Aqueous, Water based ink which typically ♦Environmentally        friendly ♦Slow drying ♦IJ02, IJ04, IJ21,      IJ26        pigment contains: water, pigment, surfactant, ♦No odor      ♦Corrosive ♦IJ27, IJ30         humectant, and biocide. ♦Reduced bleed ♦Pi       gment may clog nozzles ♦Silverbrook, EP 0771         Pigments have an advantage in ♦Reduced wicking .diamond-       solid.Pigment may clog actuator 658 A2 and related         reduced bleed, wicking and ♦Reduced strikethrough      mechanisms patent applications         strikethrough.  ♦Cockles paper ♦Piezoelect       ric ink-jets            ♦Thermal ink jets            (with significant            restrictions)        Methyl Ethyl MEK is a highly volatile solvent ♦Very fast        drying ♦Odorous ♦All IJ series ink jets          Ketone (MEK) used for industrial printing on ♦Prints      on various substrates ♦Flammable         difficult surfaces such as aluminum such as metals and plastics              cans.        Alcohol Alcohol based inks can be used ♦Fast drying      ♦Slight odor ♦All IJ series ink jets               (ethanol, 2- where the printer must operate at ♦Op       erates at sub-freezing ♦Flammable        butanol, and temperatures below the freezing temperatures        others) point of water. An example of this is ♦Reduced      paper cockle         in-camera consumer photographic ♦Low cost         printing.        Phase change The ink is solid at room temperature, ♦No      drying time-ink ♦High viscosity ♦Tektronix      hot melt        (hot melt) and is melted in the print head before instantly freezes on        the ♦Printed ink typically has a `waxy`       feel piezoelectric ink jets         jetting. Hot melt inks are usually print medium ♦Printed        pages may `block` ♦1989 Nowak U.S. Pat. No.         wax based, with a melting point ♦Almost any print      medium ♦Ink temperature may be above the 4,820,346                around 80° C. After jetting the ink can be used curie      point of permanent magnets ♦All IJ series ink jets                freezes almost instantly upon ♦No paper cockle      occurs ♦Ink heaters consume power         contacting the print medium or a ♦No wicking occurs      ♦Long warm-up time         transfer roller. ♦No bleed occurs          ♦No strikethrough occurs        Oil Oil based inks are extensively used ♦High solubility        medium for ♦High viscosity: this is a significant      ♦All IJ series ink jets         in offset printing. They have some dyes limitation for use in      inkjets, which         advantages in improved ♦Does not cockle paper usually      require a low viscosity. Some         characteristics on paper (especially ♦Does not wick      through short chain and multi-branched oils         no wicking or cockle.). Oil soluble paper have a sufficiently low      viscosity.         dies and pigments are required.  ♦Slow drying        Microemulsion A microemulsion is a stable, self ♦Stops      ink bleed ♦Viscosity higher than water ♦All      IJ series ink jets         forming emulsion of oil, water, and ♦High dye solubility        ♦Cost is slightly higher than water based         surfactant. The characteristic drop ♦Water, oil, and      amphiphilic ink         size is less than 100 nm, and is soluble dies can be used .diamond-sol       id.High surfactant concentration required         determined by the preferred ♦Can stabilize pigment      (around 5%)         curvature of the surfactant. suspensions

Ink Jet Printing

A large number of new forms of ink jet printers have been developed to facilitate alternative ink jet technologies for the image processing and data distribution system. Various combinations of ink jet devices can be included in printer devices incorporated as part of the present invention. Australian Provisional Patent Applications relating to these ink jets which are specifically incorporated by cross reference include:

    __________________________________________________________________________     Australian                                                                                     Provisional                                                      Number Filing Date Title                                                     __________________________________________________________________________     PO8066  Jul-15-97                                                                             Image Creation Method and Apparatus (IJ01)                        PO8072 Jul-15-97 Image Creation Method and Apparatus (IJ02)                    PO8040 Jul-15-97 Image Creation Method and Apparatus (IJ03)                    PO8071 Jul-15-97 Image Creation Method and Apparatus (IJ04)                    PO8047 Jul-15-97 Image Creation Method and Apparatus (IJ05)                    PO8035 Jul-15-97 Image Creation Method and Apparatus (IJ06)                    PO8044 Jul-15-97 Image Creation Method and Apparatus (IJ07)                    PO8063 Jul-15-97 Image Creation Method and Apparatus (IJ08)                    PO8057 Jul-15-97 Image Creation Method and Apparatus (IJ09)                    PO8056 Jul-15-97 Image Creation Method and Apparatus (IJ10)                    PO8069 Jul-15-97 Image Creation Method and Apparatus (IJ11)                    PO8049 Jul-15-97 Image Creation Method and Apparatus (IJ12)                    PO8036 Jul-15-97 Image Creation Method and Apparatus (IJ13)                    PO8048 Jul-15-97 Image Creation Method and Apparatus (IJ14)                    PO8070 Jul-15-97 Image Creation Method and Apparatus (IJ15)                    PO8067 Jul-15-97 Image Creation Method and Apparatus (IJ16)                    PO8001 Jul-15-97 Image Creation Method and Apparatus (IJ17)                    PO8038 Jul-15-97 Image Creation Method and Apparatus (IJ18)                    PO8033 Jul-15-97 Image Creation Method and Apparatus (IJ19)                    PO8002 Jul-15-97 Image Creation Method and Apparatus (IJ20)                    PO8068 Jul-15-97 Image Creation Method and Apparatus (IJ21)                    PO8062 Jul-15-97 Image Creation Method and Apparatus (IJ22)                    PO8034 Jul-15-97 Image Creation Method and Apparatus (IJ23)                    PO8039 Jul-15-97 Image Creation Method and Apparatus (IJ24)                    PO8041 Jul-15-97 Image Creation Method and Apparatus (IJ25)                    PO8004 Jul-15-97 Image Creation Method and Apparatus (IJ26)                    PO8037 Jul-15-97 Image Creation Method and Apparatus (IJ27)                    PO8043 Jul-15-97 Image Creation Method and Apparatus (IJ28)                    PO8042 Jul-15-97 Image Creation Method and Apparatus (IJ29)                    PO8064 Jul-15-97 Image Creation Method and Apparatus (IJ30)                    PO9389 Sep-23-97 Image Creation Method and Apparatus (IJ31)                    PO9391 Sep-23-97 Image Creation Method and Apparatus (IJ32)                    PP0888 Dec-12-97 Image Creation Method and Apparatus (IJ33)                    PP0891 Dec-12-97 Image Creation Method and Apparatus (IJ34)                    PP0890 Dec-12-97 Image Creation Method and Apparatus (IJ35)                    PP0873 Dec-12-97 Image Creation Method and Apparatus (IJ36)                    PP0993 Dec-12-97 Image Creation Method and Apparatus (IJ37)                    PP0890 Dec-12-97 Image Creation Method and Apparatus (IJ38)                    PP1398 Jan-19-98 An Image Creation Method and Apparatus (IJ39)                 PP2592 Mar-25-98 An Image Creation Method and Apparatus (IJ40)                 PP2593 Mar-25-98 Image Creation Method and Apparatus (IJ41)                    PP3991 Jun-9-98 Image Creation Method and Apparatus (IJ42)                     PP3987 Jun-9-98 Image Creation Method and Apparatus (IJ43)                     PP3985 Jun-9-98 Image Creation Method and Apparatus (IJ44)                     PP3983 Jun-9-98 Image Creation Method and Apparatus (IJ45)                   __________________________________________________________________________

Ink Jet Manufacturing

Further, the present application may utilize advanced semiconductor fabrication techniques in the construction of large arrays of ink jet printers. Suitable manufacturing techniques are described in the following Australian provisional patent specifications incorporated here by cross-reference:

    __________________________________________________________________________     Australian Provisional                                                           Number Filing Date Title                                                     __________________________________________________________________________     PO7935    15-Jul-97                                                                            A Method of Manufacture of an Image Creation Apparatus                         (IJM01)                                                          PO7936 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM02)                                                          PO7937 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM03)                                                          PO8061 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM04)                                                          PO8054 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM05)                                                          PO8065 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM06)                                                          PO8055 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM07)                                                          PO8053 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM08)                                                          PO8078 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM09)                                                          PO7933 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM10)                                                          PO7950 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM11)                                                          PO7949 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM12)                                                          PO8060 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM13)                                                          PO8059 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM14)                                                          PO8073 15-Jul-91 A Method of Manufacture of an Image Creation Apparatus                      (IJM15)                                                          PO8076 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM16)                                                          PO8075 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM17)                                                          PO8079 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM18)                                                          PO8050 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM19)                                                          PO8052 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM20)                                                          PO7948 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM21)                                                          PO7951 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM22)                                                          PO8074 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM23)                                                          PO7941 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM24)                                                          PO8077 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM25)                                                          PO8058 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM26)                                                          PO8051 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM27)                                                          PO8045 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM28)                                                          PO7952 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM29)                                                          PO8046 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM30)                                                          PO8503 11-Aug-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM30a)                                                         PO9390 23-Sep-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM31)                                                          PO9392 23-Sep-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM32)                                                          PP0889 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM35)                                                          PP0887 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM36)                                                          PP0882 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM37)                                                          PP0874 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus                      (IJM38)                                                          PP1396 19-Jan-98 A Method of Manufacture of an Image Creation Apparatus                      (IJM39)                                                          PP2591 25-Mar-98 A Method of Manufacture of an Image Creation Apparatus                      (IJM41)                                                          PP3989 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus                       (IJM40)                                                          PP3990 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus                       (IJM42)                                                          PP3986 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus                       (IJM43)                                                          PP3984 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus                       (IJM44)                                                          PP3982 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus                       (IJM45)                                                        __________________________________________________________________________

Fluid Supply

Further, the present application may utilize an ink delivery system to the ink jet head. Delivery systems relating to the supply of ink to a series of ink jet nozzles are described in the following Australian provisional patent specifications, the disclosure of which are hereby incorporated by cross-reference:

    ______________________________________                                         Australian                                                                       Provisional                                                                    Number Filing Date Title                                                     ______________________________________                                         PO8003    15-Jul-97  Supply Method and Apparatus (F1)                            PO8005 15-Jul-97 Supply Method and Apparatus (F2)                              PO9404 23-Sep-97 A Device and Method (F3)                                    ______________________________________                                    

MEMS Technology

Further, the present application may utilize advanced semiconductor microelectromechanical techniques in the 10 construction of large arrays of ink jet printers. Suitable microelectromechanical techniques are described in the following Australian provisional patent specifications incorporated here by cross-reference:

    ______________________________________                                         Australian                                                                       Provisional                                                                    Number Filing Date Title                                                     ______________________________________                                         PO7943    15-Jul-97  A device (MEMS01)                                           PO8006 15-Jul-97 A device (MEMS02)                                             PO8007 15-Jul-97 A device (MEMS03)                                             PO8008 15-Jul-97 A device (MEMS04)                                             PO8010 15-Jul-97 A device (MEMS05)                                             PO8011 15-Jul-97 A device (MEMS06)                                             PO7947 15-Jul-97 A device (MEMS07)                                             PO7945 15-Jul-97 A device (MEMS08)                                             PO7944 15-Jul-97 A device (MEMS09)                                             PO7946 15-Jul-97 A device (MEMS10)                                             PO9393 23-Sep-97 A Device and Method (MEMS11)                                  PP0875 12-Dec-97 A Device (MEMS12)                                             PP0894 12-Dec-97 A Device and Method (MEMS13)                                ______________________________________                                    

IR Technologies

Further, the present application may include the utilization of a disposable camera system such as those described in the following Australian provisional patent specifications incorporated here by cross-reference:

    ______________________________________                                         Australian                                                                       Provisional                                                                    Number Filing Date Title                                                     ______________________________________                                         PO0895    12-Dec-97  An Image Creation Method and                                  Apparatus (IR01)                                                             PP0870 12-Dec-97 A Device and Method (IR02)                                    PP0869 12-Dec-97 A Device and Method (IR04)                                    PP0887 12-Dec-97 Image Creation Method and                                       Apparatus (IR05)                                                             PP0885 12-Dec-97 An Image Production System (IR06)                             PP0884 12-Dec-97 Image Creation Method and                                       Apparatus (IR10)                                                             PP0886 12-Dec-97 Image Creation Method and                                       Apparatus (IR12)                                                             PP0871 12-Dec-97 A Device and Method (IR13)                                    PP0876 12-Dec-97 An Image Processing Method and                                  Apparatus (IR14)                                                             PP0877 12-Dec-97 A Device and Method (IR16)                                    PP0878 12-Dec-97 A Device and Method (IR17)                                    PP0879 12-Dec-97 A Device and Method (IR18)                                    PP0883 12-Dec-97 A Device and Method (IRI9)                                    PP0880 12-Dec-97 A Device and Method (IR20)                                    PP0881 12-Dec-97 A Device and Method (IR21)                                  ______________________________________                                    

DotCard Technologies

Further, the present application may include the utilization of a data distribution system such as that described in the following Australian provisional patent specifications incorporated here by cross-reference:

    ______________________________________                                         Australian                                                                       Provisional                                                                    Number Filing Date Title                                                     ______________________________________                                         PP2370    16-Mar-98  Data Processing Method and                                    Apparatus (Dot01)                                                            PP2371 16-Mar-98 Data Processing Method and                                      Apparatus (Dot02)                                                          ______________________________________                                    

Artcam Technologies

Further, the present application may include the utilization of camera and data processing techniques such as an Artcam type device as described in the following Australian provisional patent specifications incorporated here by cross-reference:

    ______________________________________                                         Australian                                                                       Provisional                                                                    Number Filing Date Title                                                     ______________________________________                                         PO7991    15-Jul-97  Image Processing Method and                                   Apparatus (ART01)                                                            PO8505 11-Aug-97 Image Processing Method and                                     Apparatus (ART01a)                                                           PO7988 15-Jul-97 Image Processing Method and                                     Apparatus (ART02)                                                            PO7993 15-Jul-97 Image Processing Method and                                     Apparatus (ART03)                                                            PO8012 15-Jul-97 Image Processing Method and                                     Apparatus (ART05)                                                            PO8017 15-Jul-97 Image Processing Method and                                     Apparatus (ART06)                                                            PO8014 15-Jul-97 Media Device (ART07)                                          PO8025 15-Jul-97 Image Processing Method and                                     Apparatus (ART08)                                                            PO8032 15-Jul-97 Image Processing Method and                                     Apparatus (ART09)                                                            PO7999 15-Jul-97 Image Processing Method and                                     Apparatus (ART10)                                                            PO7998 15-Jul-97 Image Processing Method and                                     Apparatus (ART11)                                                            PO8031 15-Jul-97 Image Processing Method and                                     Apparatus (ART12)                                                            PO8030 15-Jul-97 Media Device (ART13)                                          PO8498 11-Aug-97 Image Processing Method and                                     Apparatus (ART14)                                                            PO7997 15-Jul-97 Media Device (ART15)                                          PO7979 15-Jul-97 Media Device (ART16)                                          PO8015 15-Jul-97 Media Device (ART17)                                          PO7978 15-Jul-97 Media Device (ART18)                                          PO7982 15-Jul-97 Data Processing Method and                                      Apparatus (ART19)                                                            PO7989 15-Jul-97 Data Processing Method and                                      Apparatus (ART20)                                                            PO8019 15-Jul-97 Media Processing Method and                                     Apparatus (ART21)                                                            PO7980 15-Jul-97 Image Processing Method and                                     Apparatus (ART22)                                                            PO7942 15-Jul-97 Image Processing Method and                                     Apparatus (ART23)                                                            PO8018 15-Jul-97 Image Processing Method and                                     Apparatus (ART24)                                                            PO7938 15-Jul-97 Image Processing Method and                                     Apparatus (ART25)                                                            PO8016 15-Jul-97 Image Processing Method and                                     Apparatus (ART26)                                                            PO8024 15-Jul-97 Image Processing Method and                                     Apparatus (ART27)                                                            PO7940 15-Jul-97 Data Processing Method and                                      Apparatus (ART28)                                                            PO7939 15-Jul-97 Data Processing Method and                                      Apparatus (ART29)                                                            PO8501 11-Aug-97 Image Processing Method and                                     Apparatus (ART30)                                                            PO8500 11-Aug-97 Image Processing Method and                                     Apparatus (ART31)                                                            PO7987 15-Jul-97 Data Processing Method and                                      Apparatus (ART32)                                                            PO8022 15-Jul-97 Image Processing Method and                                     Apparatus (ART33)                                                            PO8497 11-Aug-97 Image Processing Method and                                     Apparatus (ART30)                                                            PO8029 15-Jul-97 Sensor Creation Method and                                      Apparatus (ART36)                                                            PO7985 15-Jul-97 Data Processing Method and                                      Apparatus (ART37)                                                            PO8020 15-Jul-97 Data Processing Method and                                      Apparatus (ART38)                                                            PO8023 15-Jul-97 Data Processing Method and                                      Apparatus (ART39)                                                            PO9395 23-Sep-97 Data Processing Method and                                      Apparatus (ART4)                                                             PO8021 15-Jul-97 Data Processing Method and                                      Apparatus (ART40)                                                            PO8504 11-Aug-97 Image Processing Method and                                     Apparatus (ART42)                                                            PO8000 15-Jul-97 Data Processing Method and                                      Apparatus (ART43)                                                            PO7977 15-Jul-97 Data Processing Method and                                      Apparatus (ART44)                                                            PO7934 15-Jul-97 Data Processing Method and                                      Apparatus (ART45)                                                            PO7990 15-Jul-97 Data Processing Method and                                      Apparatus (ART46)                                                            PO8499 11-Aug-97 Image Processing Method and                                     Apparatus (ART47)                                                            PO8502 11-Aug-97 Image Processing Method and                                     Apparatus (ART48)                                                            PO7981 15-Jul-97 Data Processing Method and                                      Apparatus (ART50)                                                            PO7986 15-Jul-97 Data Processing Method and                                      Apparatus (ART51)                                                            PO7983 15-Jul-97 Data Processing Method and                                      Apparatus (ART52)                                                            PO8026 15-Jul-97 Image Processing Method and                                     Apparatus (ART53)                                                            PO8027 15-Jul-97 Image Processing Method and                                     Apparatus (ART54)                                                            PO8028 15-Jul-97 Image Processing Method and                                     Apparatus (ART56)                                                            PO9394 23-Sep-97 Image Processing Method and                                     Apparatus (ART57)                                                            PO9396 23-Sep-97 Data Processing Method and                                      Apparatus (ART58)                                                            PO9397 23-Sep-97 Data Processing Method and                                      Apparatus (ART59)                                                            PO9398 23-Sep-97 Data Processing Method and                                      Apparatus (ART60)                                                            PO9399 23-Sep-97 Data Processing Method and                                      Apparatus (ART61)                                                            PO9400 23-Sep-97 Data Processing Method and                                      Apparatus (ART62)                                                            PO9401 23-Sep-97 Data Processing Method and                                      Apparatus (ART63)                                                            PO9402 23-Sep-97 Data Processing Method and                                      Apparatus (ART64)                                                            PO9403 23-Sep-97 Data Processing Method and                                      Apparatus (ART65)                                                            PO9405 23-Sep-97 Data Processing Method and                                      Apparatus (ART66)                                                            PP0959 16-Dec-97 A Data Processing Method                                        and Apparatus (ART68)                                                        PP1397 19-Jan-98 A Media Device (ART69)                                      ______________________________________                                     

We claim:
 1. A method of constructing one or more electrically conductive portions within a substantially non-conductive material comprising embedding quantum wires of a substantially conductive material within said portions.
 2. A thermal actuator comprising a substantially non-conductive, heat expansive material having a predetermined portion thereof rendered electrically conductive by the incorporation of a series of quantum wires of a substantially conductive material.
 3. An actuator as claimed in claim 2 wherein said non-conductive, heat expansive material comprise substantially polytetrafluoroethylene.
 4. An actuator as claimed in either of claims 2 or 3 wherein said conductive material comprises substantially carbon.
 5. A thermal actuator comprising first and second layers of substantially non-conductive, heat expansive materials, wherein one of said layers incorporates quantum wires of a substantially conductive material interposed with said substantially non-conductive, expansive material.
 6. A thermal actuator as claimed in claim 5 wherein said layer incorporating said quantum wires includes predetermined non-conductive areas.
 7. An actuator as claimed in either claim 5 or claim 6 wherein said layers of non-conductive, expansive material comprises substantially polytetrafluoroethylene.
 8. An actuator as claimed in either claim 5 or claim 6 wherein said conductive material comprises substantially carbon. 